Conventional building industry practice uses prefabricated door frame assemblies which are manufactured at a manufacturing facility and then transported to a remote location for installation. This assembly includes a frame as well as a pre-hung door. The door frame includes a header jamb assembly for the top of the doorway opening in a wall and latch and hinge jamb assemblies for the sides of the doorway opening in the wall. To accommodate for variations in the thickness of the wall in which a door is located, the frame is adjustable to accommodate these wall thicknesses. Additionally, the frame should be adaptable to wide variety of uses, including the addition of a screen or storm door and the addition or omission of exterior trim.
A typical frame of this type is disclosed in U.S. Pat. No. 5,187,898 to McKann, entitled Adjustable Door Frame, the subject matter of which is hereby incorporated by reference. This frame is secured to the wall in the doorway opening by screws passing through the frame outside of and adjacent to the opening, as well as by screws passing through the portion of the frame inside the doorway opening and into the wall part defining the doorway opening. To provide a secure connection, the screws are within the normal field of vision and provide an unsightly appearance. Additionally, such screws require the use of considerable labor time by skilled installers.
Clip systems have been used for securing door frames in position. Typical clip systems are disclosed in U.S. Pat. No. 3,788,019 to Kiselewski, U.S. Pat. No. 3,545,135 to Lieber, U.S. Pat. No. 3,320,705 to Downing and U.S. Pat. No. 4,510,722 to van Wieringen.
However, these conventional clip mounting systems for door frames are not adequately simple and inexpensive to use and manufacture.